Tunnel kiln



H. R. STRAIGHT TUNNEL KILN March 20, 1928. 1,663,029

Filed May 25. 1926 Patented Mar. 20, 1928.

' NITE HALVER B. STRAIGHT, on ADEL, IOWA.

TUNNEL KILn.

Application filed May '25,

The object of my invention is to provide a tunnel kiln having improved means for introducing a fuel for burning the ware and for controlling and circulating the fuel evenly and uniformly through the ware While combustion is taking place.

Wore specifically it is the object of my invention to introduce the fuel for burning the ware at points on opposite sides of the ware, the fuel being fluid or powderedmaterial such as coal and introduced under pressure, andcaused to be delivered to the combustion chamber in such a manner that a pressure head is created above the ware by the comtion of the fuel in such a manner that the heated gases will be forced downwardly through the ware and to cause a recirculation of the products of combustion in such a manner that a blanket of the products of combustion and excess 'air may be maintained adjacent to the side faces ofthe stack of ware to protect the same against excessive temperatures and discoloration.

' A further object is to provide in a tunnel kiln, having means for feeding theproducts of combustion upwardly on opposite sides of the stack of ware, improved means for supporting the ware on suitable kiln cars, whereby the ware may be stacked with vertical passagesand have in communication therewith horizontal passages arranged transversely withthe movement of the cars, said means being so constructed that it may be arranged in such a manner to cause a uni-. form distribution of thedownwardly mow ing currents of gases passing through the ware.

A further object is to provide a floor construction for kiln cars of hollow blocks made of highly refractory material, which may be formed cheaply by being constructed on the ordinary tile machines, and serve to support a stack of ware arranged with vertical passages and arranged in such a manner that transverse and horizontal passages will be provided in communication with the vertical passages, said blocks being formed of comparatively short lengths so that passages of various lengths may be provided by simply placing a number of the blocks end to end.

My invention consists in. the construction, arrangement and combination of the various partsof the device, whereby the objects contemplated are attained, as hereinafter more 1 fully set forth, pointed out in my claims, and

1926. Serial no. 111,523.

illustrated in the accompanying drawings, in which: v

Figure l is a segmental side elevation of my improved tunnel kiln,. portions of the sides being broken away to show certain details of construction. 7 1

Figure 2 is a transverse sectional view taken on the line 22'of Figure 1,

' Figure 3 is a detail sectional view taken on the line 3-3of Figure 2.. v r

Figure 4; is a detail sectional view taken on the line 4 1 of Figure 2. f

Figure 51s a plan View showing a modified formof my improved floor construction.

The numeral 10 indicates atunnelwhich is of arch construction and substantially semicircular in cross section. The base of said arch is supported on comparatively heavy foundation members 11, which project inwardly a considerable distance so that a passage 12 is providedcentrally through the bottomof the kiln, said passage being adapted to receive the kiln cars 13 supported on suitable tracks 14. Each of sai-dkiln cars is provided with a'p1atform14t. Each edge of said platform is provided with downwardly extending members 15 designed to travel in suitable sand seals 16.

The tunnelv lO is divided into preheating, burning an cooling compartments or zones.

The preheating zone 17 1s separated'from the'burning zone 18 by partitions or walls 19, while the cooling zone 20 is separated from the burning Zone 18 by similar walls 21. The inner edges of the walls 19 and 21 are vertical and terminate at a point adjacent to the outer face of the stack of ware 22, which is supported on the kiln cars 13. The ware is stacked substantially as illustrated in Figure 2 in such a manner that a 'comparatively large chamber 28 is provided above the ware, while chambers 25, 26 and 27 are provided at the sides of the ware. The

chamber 25 is in the cooling zones, the cham ber 27 in the preheating zone, and thechamber 26 between the walls 192ml 21 in the burning zone. The stack of ware is of such height that a restricted passage28 is provided between the chambers 25', '26 and 27 vand the chamber 23, for the purpose hereinprojecting nozzles 30, which are mounted in the bottom of a substantially V-shaped groove 31, which extends the entire length of the burning zone. The top of each of the nozzles 80 is flattened in, the manner clearly illustrated in Figures Land 3. The pipe 29 is connected to a fan 32 to provide means for introducingtothe nozzles 30 a quantity ofair-under pressure, A pipe 33;

communicates with the pipe 29 at'a point near the fan '32, and provides means for introducing into the air either gas or powdered fuel, whichwill be mixed with the-air V as it is advanced through thepipe 29 and discharged through the'nozzle'30.

The stack of ware 22 is" supported means of a series of rowsfof hollow blocks 34 the said rows of blocks being arranged transversely on the platform '14, said blocks being formed with longitudinal passages 35. The blocks of each row are arrangedend to end toform whatfI shall teringroups of I blocks to form sections of various lengths,

' i'orm 'oassages the blocksin such a manner that vertical:

said rows of blocks'being spaced apart to 36. The ware is stacked on a the bottom edge of said groovebeing slightly Qbelo'withefgroove 3-5 o'ftheblocks 24:. The

top edge 10f the inner portion of the members 11 terminates 'substa-ntiallyat a point near thebottom'of the stack of ware. A blower ran 38 is provided forforcingjtresh air into one end of: the compartment 23, which is expelled through the pipe 39 at the opposite "The operation of my devieeissubstantially'as follows: Assuming that the floor has been laid on" platforms "14 and the I were '22 has been stacked thereon in the manner shown in Figure 2,'and thatthe' fans and 38 are being operated and that fuel is fed'through the pipe 33,'then it will be seen that a current of fresh air will be moved longitudinally through the compartment 23, which will be circulated through the ware in the preheating zone by means not illustrated in the drawings, the present application pertaining more specifically to the action in the burning zone.

It will be seen that as the blower 32 is operated, fuel will be discharged through the nozzles 30 at considerable velocity, The nozzles are so located that the fuel will be discharged upwardly against the inner face of the arch 10, which willthen; move upwardly through the re stricted passage '28 into the chamber 23.

V 7 It should be bornefinniind that this action -is ta'k'ing'place on both sides of the kiln,-

the pressure being substantially the same on both sides; The mixture of fuel and air from the fan 82 and the pipe 33 is such that combustion is incomplete in the chamber 26, and will be co npleted in the chamber 23 where it is mixed with the excess of pre heated air. It will be seen that considerable amount oi pressure will be created by the "combustionof the fuels which will cause the heated gases to move downwardly through the vertical passages' n; the ware '22. It will further-be seen that on account of the upwardly moving gases fromthe- 'nozzle'30, a parti'a'l vacuum will be'created adjacent to the outer faces ot'the stack of ware in the stip'pled area of the drawings indicated by-the numeral 40, so that a suction is established in'the outer ends of the passages 85 Thus it will be seen that the products of combustion and the cooler gases will be drawn upwardly into the area 40 adjacent to the outer faces of'the stackof ware, form'- ing a recirculation. The products of coinbustion in the area 40 also servefto blanket the outer surface of the stack of ware against the action or" the free carbonaceous substantances of the fuels as they are discharged from the nozzles 30, therebyprote cting to a considerable extent the outer face ofthe ware against discoloration, and also against the rapidly varying temperaltures due tethe uneven burning of the fuel in'the chamber 726. The blanketjarea 4c0vis of substantially uniform temperature, due to the presence or theproducts "o f combustion attliat point. v I

'It will be seen that by providingja fiqor groups of blocks, have provided means whereby the proper downward circulation of the gases maybe; adjusted, which maybe done by the prope'ryarrangement of the groups in the r'rows, which may be easily accomplished, due to'the fact that the'blocks are of comparatively short lengths. In Figure 5 I have, shown a somewhat different arrangement from that illustrated ure 3; It will be seen in Figure?) that each alternate outer group is provided with two locksand each of the other alternate groups 'is provided with three blocks, while in Fig ure.5 each of the said groups isprov'ided with one less block. In Figure 5 it will'be seen that more gases may be moved 'downwardly near the outer faces of .the ware than would hein the arrangement illustrated in Figure The downward circulation of the gases may be also vvaried by the spacing between the rows of blocks. This spacing,

however is somewhat dependent upon the length of the blocks of ware stacked thereon. It will "be seen that considerable "advantage is gained by locating the upper endsot construction "of hollow blocks arranged in rows, each of 'the'rows being formed in the nozzles at a point'somewhat-below the bottom line of the stack of ware and below the passages 35, and in providing the upwardly projecting portion ll of the wall 11 between the discharge ends of the nozzles 30 and the outer ends of the passages 34:,- so that there will be a considerable tendency toward forming a'vacuum in the groove 37.

A considerable advantage'is also gained in providing the restricted passage 28, which will greatly increase the velocity of the gases at that point, and cause more complete mixing of the products of combustion and excess air recirculated with the combustible just introduced, causing an increased pressure head at the central portion of the chamber 28, due to the momentum of incoming gases. I v r 'Thus it will be seen that if the fans 32 and 38 are continuously operated, fuel will be continuously fed to the chamber 23 and combustion will take place in a continuous manner as the ware is being advanced through the burning chamber, and that a continuous downward draft of heated gases will be maintained. It should be borne in mind that the natural tendency of the heated gases is to move downwardly after being introduced into the vertical passages, due to the cooling eifect of the ware. The gases are recirculated through the ware in two helical streams operating in opposite direc tions, due to the combined action of the recirculating gases and the advancing movement of the incoming pure air.

Thus it will be seen I have provided a kiln of simple, durable and inexpensive construction, in which the burning of the ware may be uniformly maintained throughout the burning zone, due to the fact that the natural laws of circulation have been economically applied, and that the counteracting resistances have been largely eliminated, thereby permitting free and uniform circulation of the gases with a minimum amount of power.

I claim as my invention:

1. In combination, a kiln car having a latform, of a ware supporting floor carried by said platform comprising a series of spaced and transverse rows of hollow tile, the tile of each row being arranged in separated groups.

2. In combination, a kiln car having a platform, of a. ware supporting floor carried by said platform comprising a series of transverse rows of hollow tile, each row comprising a number of separated sections of tile.

3. In combination, a kiln car having a platform, of a ware supporting floor carried by said platform comprising a series of spaced and transverse rows of hollow tile, the tile of each row being arranged in separated groups, the groups of one row being in staggered relation to those of an adjacent row. V t

4t. In combination, a kilncar having a platform, of-a ware supporting floor carried by said platform comprising a series vof spaced and transverse rows of hollow tile,

the tile of each rowbeing arranged in sepgroups of said rows 'ofigroups being inv common longitudinal alinem ent.v

6. In combination, a tunnel, a kiln car, means carried by said car. for supporting ware thereon, means for-circulating a'fiuid downwardly through said ware then outwardly beneath said ware, comprising .a

series of supporting members for said ware arranged to form transverse passages, said supporting members being arranged to form passages of various lengths to cause a unrform downward movement of the fluid through the ware.

7. In combination, a tunnel kiln, means for conveying a stack of ware having vertical and transverse passages longitudinally through said tunnel kiln, said tunnel kiln being constructed with a mixing chamber at each side of the stack of ware and a combustion chamber above the Ware, said combustion and mixing chambers communicating by restricted passage, the bottom of each of said mixing chambers beingprovided with a series of vertically projectingfuel delivery nozzles, the discharge end of said nozzles being below the lower line of said stack of ware and arranged to discharge the fuel upwardlyand somewhat spaced from the outerfa'ce of said stack of were 8. In combination, a tunnel kiln, means for conveying a stack of ware having vertical and transverse passages longitudinally through said tunnel kiln, said tunnel kiln being constructed with a mixing chamber at each side of the stack of ware and a combustion chamber above the ware, said con1- bustion and mixing chambers communicating by a restricted passage, the bottom of each of said mixing chambers being pro- 7 vided with series of vertically projecting fuel delivery nozzles,the discharge end of said nozzles beingbelow the lower line of said stack of ware and arranged todischarge the fuel upwardly and somewhat spaced from the outer face of said stack of ware, means for delivering a fluid fuel under pressure to said nozzles, and means for advancing air longitudinally through the combustion chamber. 7

9. In combination, a; tunnel kiln,- means for conveylng a stack of ware'havlng vertical and I transverse passages longitudinally through said tunnel, saidtunnel beingconstructed with a mixing chamber at one-side of sald stack of ware and a combustion chamber above the ware,v said combustion chamber and said mixing chamber communicatlng by a restrictedpassage,v thebottom of said mixing-- chamber being provided with ayertical projecting'fuel delivery nozzle, the discharge end of said nozzle being below the lower line of said stack of ware, for the purposes stated. A

W10. In. combination, a: tunnelkiln, means 7 V fol-conveying a stack of ware having vertical and-i transverse passages longitudinally through said't'unneli. said tunnel being conof saidmixing chamber beingprovided with a vertically projectingfuel'delivefy nozzle, the dischargeend of saidnozzlebeing below 1 the lower line of said stack 'ofware, said nozzle being located outwardly from; the

ware so that the fuel discharged-' therefrom will be moved-upwardly some distance from the outen surface of thestack of ware ,to forminduetion area in communication with the outer endof said transverse pass sages.

11; In combinatioma tunnel kiln, means,

for conveyingfla stack of ware having vertical and transversepassages longitudinally through said-tunnel said tunnelbeing con structed with amixing chamber at each side ofthesta'ck of ware and'a combustioncham: ber above, the Ware, said combustion and mixingch'ambers j communicating; by, ;-re:-"

stricted passages,- the bottomof each mixingk chamber being;- provide'diwith a ver; a

tically projecting fuel delivery. nozzle, the discharge end of said nozzle being below the floor line of said stack of ware and said transversepassages, and outwardly from the discharge endof said passages a considerable distance,-means for feeding fuel and air to. said nozzles in such proportions as-to forman incomplete combustion in said mixing chamber,- and means for feeding pure air to said combustion chamber, substantially as described and for the purposes stated. i 7

Des 'M0ines,vIowa,'May 17, 1926.

HALVER' R. STRAIGHT. 

